Many applications require isolation of different supply voltages, in particular isolation of reference potentials such as ground potentials in different voltage domains. Thus, the demand for isolated supply voltage is increasing. In recent industrial applications, the need for electrical isolation, both Galvanic and direct current (DC)-to-DC, is increasing for both data communication and DC supply voltages, e.g., at differing ground potentials. The typical isolation application has been mainly for data communications across an isolation barrier. But in recent years, applications are demanding that the isolation device (for data communication) also include isolated DC-to-DC energy transfer capabilities as well.
Typical electrical isolation methods may include: optical, inductive, e.g., using alternating current (AC) through a transformer or electromagnetic radio frequencies, capacitor (capacitor is a very good galvanic isolator), etc. Optical couplers have been the dominant signal isolation device but are limited to slow data rates (less than 1 MHz) and are bulky to integrate. Moreover, the optical coupler is not capable of passing isolated DC power. Inductive and capacitive isolation implementations provide for high data rates, offer electrically isolated power transfer, and are low-cost to manufacture. Demand is very high for Galvanic isolation between devices in different voltage domains to have isolation of, for example, 1 kVrms, 2.5 kVrms, 4 kVrms, etc.